Method of providing fuel gas for coking retort ovens



J.BECKER Sept. 6, 1932.

METHOD OF PROVIDING FUEL GAS FOR COKING RETORT OVENS Filed Feb. 19. 19294 Sheets-Sheet l INVENTOR. ese/0b Sec/heft sept 6 1932 J. BECKER1,876,037

METHOD OF PROVIDING FUEL GAS FOR COKING RETORT OVENS 4 VSheets-Sheet 2Filed Feb. 1S. 1929 INVENTOR. Q/Qseyoh Bec/fer BY f y ATTRN ff/ J.BECKER Sept. 6, 1932.

METHOD 0F PROVIDING FUEL GAS FOR COKING RETORT OVENS Filed Feb. 19. 19294 Sheets-Sheet 4 Patented Sept. 6. 1932 UNITED STATE s PATENT oFFlcEJOSEPH BECKER, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE KOPPERSCO'M- PANY 0F DELAWARE, A CORPORATIONOF DELAWARE METHOD OF PROVIDNGFUEL? GAS FOR COKING RETORT OVENS- l Application filed February 19,1929. Serial No.` 341,240.

My invention relates to heating systems for coking retort ovens andparticularly to means for utilizing blast-furnace gases for heating theoven chambers of coking retort ovens.

An obj ect of my invention is to provide means whereby blast-furnacegases from one or a plurality of sources may be utilized moreeffectively. and economically as fuel gas for underiring coke-ovenbatteries.

Myinvention has also for its further'ob-` jects such other advantagesand improvements as may be found to obtain Withrespect to it ashereinafterdescribed or claimed.

In the operation of coke-oven batteries, it is very essential that theB. t. u. value .of the fuel gas be substantially uniform inasmuch as therelative quantity of air that is, in proportion to that of gas, isordinarily limited by flow conditions that have to be maintained.However, a variation in the B. t. u. value of the gas correspondinglychanges the amount of air required for perfect combustion. If the gasexceeds the normal B. t. u. value, the quantity of air is insufficientvand imperfect combustion results. If the gas is too lean,

there is a surplus of air and the result is to cool the ovens by reasonofthe heat required to bring the excess air up to the temperature of thegases of combustion.

The supplying of fuel gas at a definite B. t. u. value insures a uniformapplication of heat to the coking mass, with the result that a uniformcoke is produced from any good coal and uniformity and regularity ofcoking operations is secured.

In the normal operation of acoke plant in Whichfa part of the coke-ovengas'thatis produced is used as fuel gas to heat the ovens, thecoke-roven gas has an average thermal value of 530 B. t. u. Thevariation in the thermal value of the gas does not exceed more thanapproximately l5 B. t. u.s, representing ajfluctuation offabout 3%. This`percentage of variationl is so small that from a practical standpointit is not necessary t o provide means for maintaining the B. t. u. valueconstant atany predetermined value. The regulation of the B. t. u. valueof cokeoven gas might be accomplished by supplying the small amount ofair or inert gas needed to maintain the thermal value at the minimum B.t. u. value of the coke-oven gas.

' Lean gas is especially suitable for under- L frinor coke-ovenbatteries because of the readi y obtained uniform vertical distributionof the heat of combustion, since the combustion of such gas tends tooccur throughout substantially ythe entire length of the vflame fiues.When gas of this' character is employed as a fuel, the quality of cokeaverages very high because of the uniform heating conditions throughoutthe vertical height of the ovens.

In the operation of blast furnaces in connectionwith steel mills andother similar plants, considerable gas is generated that may be utilizedas a fuel gas but which isy of very low B. t. u. value.` By reason ofthe methods of operation of blast furnaces, the gas varies such` degreeof uniformity of B. t. u. value that the coking results are comparablewith those of operatlonwithcoke-oven gas, even though coke-oven gas iseffectively used without correction of its thermal value. Otherwise, the

coking time required for any given coal is l unduly prolonged and madeirregular by the loss in heat when the B. t. u. value of theblastfurnace gas is below its maximum value. l

4 It may be assumed that a coke plant has a coking time of 16 hours whenthe ovens are heated with coke-oven gas. If, when heated l Withblast-furnace gas, there be a variation in It will be readilyseenthat'such.

' the B. t. u. value ofthe gas such that there is y a delay of even only15%, such delay would be"- plant had a defeat the effective or economicuse 'of blastfurnace gas in coke ovens.

The manual regulation of very lean gas,

ioo

. B. t. u. blast-furnace gas and thus release thev such as blast-furnacegas, is very difficult since it is not practicable to determine by merevisualv inspection whether the combustion is normal, the combustionoccurring substantially without visible ames, and the variations of B.t. u. value in the blast-furnace gas may be too large and frequent.

I havel found, however, that blast-furnace gas from one or more sourcesand that is even highly variable in yits B. t. u. value may be used withhigh eiiciency to produce coke of high and uniform quality, by providingmeans for insuring a constant B. t. u. value of the gas. In general, theB. t. u. value of the gas is regulated ,by means of a calorimeter whichcontrols a valve to admit more or -less `coke-oven gas tocorrespondingly vary the B. t. u. value of the blast-furnace as, therebyinsuring a constant B. t. u'."value or the mixture.

When blast-furnace gas is used in the manner above stated, the coke-ovenbattery will operate smoothly and eiiciently. When so used,blast-furnace gas is at least the equal of coke-oven gas as a fuel forheating coke ovens. The coke'produced-is 0f very high quality becauseofthe uniform vertical distribution of the combustion of the fuel gasand the short coking time and regular coking schedule/may be maintainedby maintaining a uniform inflow of heat into the coking mass in all theovens of the battery.

Also, if the blast furnaces be supplied with coke from` ovens underiredwith blast-furnace gas of regulated B) t. u.'value, the operation of theblast furnaces becomes more nearly constant, due to the use of uniformcoke, and, consequently, the variations in the B. t. u. value of theblast-furnace gasare materially diminished. When such use ofblast-furnace gas and such use of coke from the ovens so fired I isemployed, there results a considerable decrease in the fluctuations ofthe blast-furnace gas, with a resultant decrease in the quantity4 yofcoke-oven gas that is required to be utilized bythe regulating.lapparatus.

, An important economygis effected by the use fof blast-furnace gas forfuel purposes in that it `releases valuable coke-oven gas for use asheating gas for commercial or domestic purposes. For example, in theproduction of a .ton of pig iron, approximately one ton of coke is used,with the production'of about 130,000

cu. ft.of-blastfurnace gas with va thermalv 'mal amount of 530 B. t. u.coke-oven gas re-l' `quired to carbonize coal to produce one ton ofvalue of about-90y B. t. u. per cu.f t. The norcoke is 6400 cu. ft. Thiscarbonization may be effected `by about 40,000 cu. ft. of the 90 6400cu. ft. ofmuch more valuable coke-oven gat-'z for other purposes forwhich blast-furnace gas is wholly unsuitable.

Y,When the relatively'lean blast-furnace gas is employed as a fuel, 'thevolume Of'th gases of combustion is greater than that when richer ,gasis employed. However, by reason of the regulation of the lblast-furnacevgas to its maximum B. t. u. value, only a sllght 1ncrease in thecross-sectlonal dimensions of certain of the passageways of the view ofsuch battery on the section lines indicated in Fig. 2;

Fig. 4 is a plan View of a mixing-device, parts being broken away; and-Fig. 5 is a view in transverse section taken along the line V--V of Fig.4.

Referring particularly to Fig. oven plant comprising a battery 1 ofcoking retort ove-ns is adapted to be supplied with fuel from a sourceof blast-furnace gas com- 1, a cokeprising a blast furnace'2. The gasfrom the blast furnace 2 flows through a pipe 3, scrubbers 4 andboosters 5 to a-gas holder 6 of any usual or suitable construction.

Gas from the holder 6 flows through a pipe 7, a mixing device 8 andpipes 9, 10, and 11 to the distributing mains 12 and 13 of thebattery- 1. The collecting main 15 of the battery 1 is connected by apipe 16 to the usual scrubbers 17 and boosters 18 for cleaning the gasand for increasing its pressure for conducting it through a pipe 19 toany suitable storage device (not shown). A branch pipe 20 connects thepipe 19 through a pipe 2l, ameter 22 and a pipe line 23 to the mixingdevice 8 for a purpose' to be herei inafter described.

A calorimeter 24 of standard construction for measuring the thermalvalue of gas supplied thereto, and provided with a burner adaptedto`serve for blast-furnace gas, is'

connected b-y a pipe 25 to the pipe 9 which supplies fuel gas to thebattery 1. An electrical measuring device 26, which is also of standardconstruction, is connected to the calorimeter 24 and controls theelectrical connections of an electric motor 27 that operates Beckerregenerative type that are arranged to be` operated either withcoke-oven gas or blast-furnace gas for. heating the ovens. The

battery comprisesa ,foundation 30 immedi- 'l Aately above which arelocated the regenerators 31 and 32 which extend transversely orlcross-Wise of the battery for half lthe Width of the latter.

A AAbove the regenerators 31 and 32 are a series of oven chambers 33which alternate with heating walls 34, the outer surfaces of `Whichconstitute the sides of the oven chambers 33. Brickwork 35 constitutes afloor for the oven chambers and a roof for the reizo generators 31 and32. The battery is provided with a top 36, through which extend 39 areeach connected by a duct 44 to a horizontal flue 45 which extendssubstantially the length of the heating Wall. rlhe horizontal .flues 45are connected by six crossover lues Each of the oven chambers 33 isprovided with an ol-take opening 47 to which is connected an ascensionpipe 48 and the collecting main for conducting the gases and otherproducts of distillation from the battery.

" The distributing mains 12 and 13 for supplying blast-furnace gas tothe battery are disposed along the respective sides of the battery andare connected to the sole flues 49 and 50, respectively, of theregenerators 31 and 32 by means of valve mechanisms 51 and 52.

The battery 1 is also suppliedwith mains 53 and 54 for supplyingcoke-oven gas to the dame lues of the heating Walls 34, through the. gasguns 43 that extend through the brickworl 35.

When the'coke-oven battery is especially adapted for blast-furnace gasoperation, the horizontal ues 45, crosover flues 38 and certain of theducts 44 are slightly enlarged as compared with the dimensions forproducer gas operation, other ducts 44 being enlarged to a greaterextent. rllhe ducts and 41 are gas is equally well adapted for producergas j since the latter is of somewhat higher thermal value andaccordingly the volume of combustion products is smaller. The cokeovenbattery shown and described herein is therefore adapted for operationWith either blast-furnace gas, producer gas or coke-oven gas 'I-hedetails of the mixing device 8 are shown in Figs. 4 and 5. The pipe 7,for introducing blast-furnace gas. from the holder 6 to the battery 1,is ,surrounded by an annular header 55, to which is connected the pipeline 23 and by means of Which the header is .sup-

plied with coke-oven gas from the main .19. The header 55 is connectedto the interior of the pipe 7 by means of a series of radially-extendingpipes 56 and 57 that are of different lengths and Which, accordingly,extend into the pipe 7 different distances, Accordingly.I

when y'gas enters the pipe 7 from the mixing' device 8, it is thoroughlydistributed with the blast-furnace gas traversing the latter to pro.duce a substantially uniform mixture.

In the operation of the heating 'system describedV above, theblast-furnace gas from the blast furnace 2 may vvary in thermal valuefrom approximately to 110 B. t. u.s. The i 4holder 6 may be and is inpractice of relatively small capacity. A small holder is possible`because correction of the blast furnace rend-A ers it unnecessary toemploy a large holder to at least partially equalize the inequalities ofthe supply of gas from the blast furnace 2 lor other'blast furnacesbefore it is supplied to the battery 1. A

As the gas flows through the pipe 7 and the various pipes andvdistributing mains to the battery, a relatively small amount flowsthrough the pipe 25 to the calorimeter 24 Which measures the thermalvalue of the gas as it is delivered to the battery. The calorimetertranslates the B. t. u. value thus measured to the electrical unit 26, amovable member of which operates in accordance with the measurement thusobtained to control the electric motor 27 and the latter adjusts thebutterfly valve 28 to admit more or less-cokeoven gas to the pipe line23.

This gas passes through the mixing device 8 and the quality of theblast-furnace gas' is thus varied 0r corrected to the predeterminedvalue for'which the calorimeter 24 is adjusted.' rllhis predeterminedvalue' is preferably.

the maximum value of the blast-furnace gas when it is not corrected. Ahigher predetermined value may be selected but it is obvious that suchvalue requires more. coke-oven gas to maintain the higher thermal valueof the corrected gas. The result is to supply the battery 1 withblast-furnace gas that has been corrected to a substantially constantvalue of approximately B. t. u.s.

.A pipe 58, having a valve 59, is provided for' use in case it isnecessary or desirable to by-passthe gas holder 6. ,Valves 60 and 61controlthe connect-ions to the holder 6 and pipe 58 is used.

` control the amount of coke-oven gas so mixed A pipe 62 may be employedwhen necessary or desirable to by-pass the meter 22, suitable valvesbeing provided for the respective conne'ctions.

While my invention has been described in connection with a single blastfurnace as a source of supply of blast-furnace gas, it is obvious thatany desired number of blast furnaces\ may be so employed. Also, Whilethe heating system has been shown and described in connection with asingle coke-oven battery, the arrangement may be extended by similarconnections from the pipe 9 to other batteries ofthe plant, one of suchbatteries 63 being indicated by dot-and-dash lines.

My invention has for its advantages the 'employment of a relativelycheap fuel gas of very low thermal value that is unsuitable for the manypurposes for which coke-oven gas may be utilized. Inasmuch as the blastfurnaces and coke ovens are often adjacent to each other particularly insteel plants, the utilization of the-'blast-furnace gas in accordancewith my invention constitutes an extremely convenient and economicalarrangement.

While I have shown and described my invention in its preferred form, itis obvious that modificati ons may occur to those skilled in the artrelating tothe operation of cokeoven plants. Accordingly, the scope ofmy invention is not limited to the particular embodiment shown hereinexcept as expressed in the claims.' l

I claim as my invention:

1. The method of providing fuel gas for coking retort ovens whichcomprises supplying blast-furnace. gas of variable thermal value, mixinga` relatively small amount of coke-oven gas with said blast-furnacegasto correct the thermal value of the latter when it falls below apredetermined value, measuring the thermal value of the gases so mixed,and then regulating the amount of coke-oven gas added to saidblast-furnace gas in according retort ovens having flame ues whichcomprises supplying blast-furnace gas that is variable between minimumand maximum thermal values, mixing a relatively `small amount ofcoke-oven gas with said blast-furnace gas, measurin the thermal value ofthe gases so mixed, emp oying the measured value JOSEPH BECKER.

ance with the measurement thus obtained to l maintain the thermal valueof the mixed gas substantially constant at approximately the maximumthermal value of the blast-furnace gas.

2. The method of providing fuel gas for coking retort ovens Whichcomprises supplying blastfurnace gas of variable thermal value, mixing arelatively small amount of cokef Iwith the blast-furnacegas to maintainsaid 'measured value substantially constant, and then supplying themixed gas to said ovens for combustion therein.

J3. The method of providingfuelgas for col(-

